This invention relates to a divided chamber type diesel engine used as a prime mover of vehicles, and more particularly relates to a divided chamber type diesel engine having an improved pre-combustion chamber with a step member for controlling the swirl.
As is well known, a divided chamber type diesel engine has a main combustion chamber and a pre-combustion chamber connected to said main combustion chamber through a connecting port. An intense swirl is generated in said pre-combustion chamber during the compression stroke of the engine.
Atmospheric pollution by exhaust gases from vehicles has become an increasingly important problem in recent years, and especially critical parts of this problem are the black smoke, nitrogen oxide NO.sub.x and offensive smells in the exhaust gases of diesel engines which are widely used in large-sized vehicles such as buses and trucks. Generally speaking, the nitrogen oxide NO.sub.x in atmosphere atomophere is harmful to the human body, i.e., for example, it stimulates the cornea of eyes and causes inflammation of the respiratory organs. Even more important in atmospheric pollution is the fact that the aforementioned nitrogen oxide NO.sub.x as well as carbonic hydrogen (hydrocarbon) gives rise to photochemical reactions which cause generation of oxidizing substances such as ozone (03), aldehyde or PAN (Pyridylazo Naphthol).
A principal object of this invention is to provide a divided chamber type diesel engine which generates less nitrogen oxide NO.sub.x in its exhaust gas than the conventional engine of the same type.
Another object of this invention is to provide a divided chamber type diesel engine having a simply constructed pre-combustion chamber, which chamber is able to control the swirl generated within itself in such a manner that, compared to conventional engines of the same type, there is less nitrogen oxide NO.sub.x generated although there are little deteriorations in the engine performances.